Inlet Air Cooling and Moisture Removal Methods and Devices in Advance Adiabatic Compressed Air Energy Storage Systems

ABSTRACT

Systems and methods provide for cooling air in a power generation system. The system includes: an air handling unit configured to receive air, to cool the air and to remove moisture from the air; a first compressor fluidly connected to the air handling unit and configured to receive the air from the air handling unit and to exhaust a first compressed, heated air flow; a vapor absorption chiller connected to the first compressor and configured to transfer heat energy between a plurality of mediums and to cool the first compressed, heated air flow; and a second compressor connected to the vapor absorption chiller and configured to receive the cooled first compressed, heated air flow and to exhaust a second compressed, heated air flow.

TECHNICAL FIELD

The embodiments of the subject matter disclosed herein generally relateto power generation systems and more specifically to advanced adiabaticcompressed air energy storage systems.

BACKGROUND

As population increases, the desire for more electrical power is alsogenerally increasing. Demand for this power typically varies during thecourse of a day with afternoon and early evening hours generally beingthe time of peak demand with later night and very early morning hoursgenerally being the time of lowest demand for power. However, powergeneration systems need to meet both the lowest and highest demandsystems for efficiently delivering power at the various demand levels.

One system attempts to solve this problem by storing energy generatedduring off-peak demand hours for use during peak demand hours. Thissystem is called an Advanced Adiabatic Compressed Air Energy Storage(AA-CAES) system and is shown in FIG. 1 as part of a power generationsystem 2. The power generation system 2 is now generally described byfollowing the path of the air flow. Initially in step 3 a, air is takeninto an axial compressor 4 and compressed during which the air is putunder pressure and undergoes an increase in temperature. This air isexhausted in step 3 b, and undergoes cooling at the Intercooler 6 to becooled to the desired temperature for further compression. The air flowis then entered in step 3 c to a first radial compressor 8. The air isthen compressed by the first radial compressor 8, exits the first radialcompressor 8 and in step 3 d enters a second radial compressor 10 forfurther compression.

The air flow then goes, in step 3 e, from the second radial compressor10 to an energy storage unit, e.g., a Thermal Energy Store 12. The hotcompressed air from the second radial compressor 10 is then cooled bythe Thermal Energy Store 12. The heat energy is stored in the ThermalEnergy Store 12 for future use and any water that is generated by thecooling process is drained off. The cooled compressed air is then sentto a Safety Cooler 14 in step 3 f, where the air is further cooled priorto being sent in step 3 g to a storage facility, e.g., cavern 16. Thisstorage of the compressed air in the cavern 16 and the storage of theenergy in the Thermal Energy Store 12 typically occurs during non-peakdemand operation of the power generation system 2.

When the demand for power from the power generation system 2 increasesto a desired point, energy output can be increased by releasing thestored compressed air back into the system to drive an expander 18,e.g., a turbine. For example, the cavern 16 releases some of the storedcompressed air, in step 3 h, to the Thermal Energy Store 12 for heating.Heat energy is transferred from the Thermal Energy Store 12 to thecompressed air and the heated compressed air flows to a particle filter20 in step 3 i. The heated compressed air then flows, in step 3 j, to anexpansion section of turbine 18. During expansion the air cools andundergoes a pressure drop while producing the work which drives theshaft 26 which in turn spins a portion of a generator 30 for powergeneration. After expansion the air flows from the turbine 18 to an airoutlet 22 in step 3 k, typically for release to atmosphere. Powergeneration system 2 can also include a shaft 24 for the compressors, agear box 28 and a motor 32.

While the system shown in FIG. 1 does allow for storing energy for useduring peak demand hours, it can be appreciated that power needs aregoing to grow and finding ways to meet the growing demand is desirable.

Accordingly, systems and methods for improving efficiency in powergeneration systems are desirable.

SUMMARY

According to an exemplary embodiment there is a system for cooling airin a power generation system. The system includes: an air handling unitconfigured to receive air, to cool the air and to remove moisture fromthe air; the first compressor fluidly connected to the air handling unitand configured to receive the air from the air handling unit and toexhaust a first compressed, heated air flow; a vapor absorption chillerconnected to the first compressor and configured to transfer heat energybetween a plurality of mediums and to cool the first compressed, heatedair flow; a second compressor connected to the vapor absorption chillerand configured to receive the cooled first compressed, heated air flowand to exhaust a second compressed, heated air flow; an energy storageunit connected to the second compressor and configured to store heatenergy from the second compressed, heated air flow; and a storagefacility connected to the energy storage unit and configured to store acooled, compressed air received from the energy storage unit and toselectively release the cooled, compressed air back into the powergeneration system.

According to another exemplary embodiment there is a system for coolingair in a power generation system. The system includes: an air handlingunit configured to receive air, to cool the air and to remove moisturefrom the air; a first compressor fluidly connected to the air handlingunit and configured to receive the air from the air handling unit and toexhaust a first compressed, heated air flow; a vapor absorption chillerconnected to the first compressor and configured to transfer heat energybetween a plurality of mediums and to cool the first compressed, heatedair flow; and a second compressor connected to the vapor absorptionchiller and configured to receive the cooled first compressed, heatedair flow and to exhaust a second compressed, heated air flow.

According to another exemplary embodiment there is a method for coolingair in a power generation system. The method includes: receiving air atan air handling unit; cooling the air at the air handling unit; removingmoisture from the air at the air handling unit; compressing air by afirst compressor; exhausting a first compressed, heated air flow fromthe first compressor; transferring heat energy between a plurality ofmediums at an vapor absorption chiller; cooling the first compressed,heated air flow at the vapor absorption chiller; compressing the cooledfirst compressed, heated air flow; and exhausting a second compressed,heated air flow.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate exemplary embodiments, wherein:

FIG. 1 depicts a power generation system and an Advanced AdiabaticCompressed Air Energy Storage (AA-CAES) system;

FIG. 2 illustrates a power generation system and an efficient AA-CAESsystem according to exemplary embodiments;

FIG. 3 shows the system of FIG. 2 with illustrative values according toexemplary embodiments;

FIG. 4 illustrates a power generation system and an another efficientAA-CAES system according to exemplary embodiments;

FIG. 5 shows the system of FIG. 4 with illustrative values according toexemplary embodiments;

FIG. 6 illustrates an air cooling system in a power generation systemaccording to exemplary embodiments;

FIG. 7 illustrates an air handler and a vapor absorption chilleraccording to exemplary embodiments;

FIG. 8 shows the system of FIG. 6 with illustrative values according toexemplary embodiments;

FIGS. 9 and 10 are flowcharts showing a method for capturing heat energyin a power generation system according to exemplary embodiments; and

FIG. 11 is a flowchart showing a method for cooling air in a powergeneration system according to exemplary embodiments.

DETAILED DESCRIPTION

The following detailed description of the exemplary embodiments refersto the accompanying drawings. The same reference numbers in differentdrawings identify the same or similar elements. Additionally, thedrawings are not necessarily drawn to scale. Also, the followingdetailed description does not limit the invention. Instead, the scope ofthe invention is defined by the appended claims.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the subject matter disclosed. Thus, theappearance of the phrases “in one embodiment” or “in an embodiment” invarious places throughout the specification is not necessarily referringto the same embodiment. Further, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreembodiments.

As described in the Background section, systems and methods forimproving efficiency in power generation systems are desirable.Exemplary embodiments described herein provide systems and methods forimproving efficiency in power generation systems. According to exemplaryembodiments, heat energy typically lost between compressors in aCompressed Air Energy Storage (CAES) system can be recovered for use ina modified adiabatic CAES (AA-CAES) system, an example of which is shownin FIG. 2.

According to exemplary embodiments, FIG. 2 shows a power generationsystem 202 which includes a modified AA-CAES system which captures andstores the heat energy, which is typically lost between an axialcompressor 204 and a radial compressor 206, for use during peak or nearpeak load conditions. By capturing this heat energy there can beapproximately an 8-10 percent improvement in overall operatingefficiency of the power generation system 202 when compared with thesystem 2 shown in FIG. 1. This system will now be described by generallyfollowing the flow of air in the system starting with an air intake tothe axial compressor 204. Initially in step 5 a, air is taken into anaxial compressor 204 and compressed during which the air is put underpressure and undergoes an increase in temperature. This air is exhaustedfrom the axial compressor 204 in step 5 b, and undergoes heat exchangein a heat exchanger, e.g., Intercooler 208, with oil which is in its ownclosed loop system. This heat exchange and the closed loop system forthe oil are explained in more detail below. The cooled air flow thenenters, in step 5 c, the first radial compressor 206. The air is thencompressed by the first radial compressor 206, exits the first radialcompressor 206 and in step 5 d enters a second radial compressor 210 forfurther compression. It is noted that more or less radial compressorsmay be used, for example the power generation system 202 can include anaxial compressor 204 and a single radial compressor 206.

The air flow then goes in step 5 e from the second radial compressor 210to an energy storage unit, e.g., a Thermal Energy Store 212. The hotcompressed air from the second radial compressor 210 is then cooled bythe Thermal Energy Store 212. The heat energy is stored in the ThermalEnergy Store 212 for future use and any water that is generated by thecooling process is drained off. The cooled compressed air is then sentto a Safety Cooler 214 in step 5 f, where the air is further cooledprior to being sent in step 5 g to a storage facility, e.g., cavern 216.This storage of the compressed air in the cavern 216 and the storage ofthe energy in the Thermal Energy Store 212 typically occurs duringnon-peak demand operation of the power generation system 202.

When the demand on the power generation system 202 increases to adesired point, energy output can be increased by releasing the storedcompressed air back into the system to drive an expander 218, e.g., aturbine. For example, the cavern 216 releases some of the storedcompressed air in step 5 h which undergoes preheating in an insulatedhot oil tank 220. The released compressed air then flows to the ThermalEnergy Store 212 for heating in step 5 i. Heat energy is transferredfrom the Thermal Energy Store 212 to the compressed air and the heatedcompressed air flows (optionally) to a particle filter 222 in step 5 j.The heated compressed air then flows in step 5 k from the particlefilter 222 to an expansion section of turbine 218. During expansion theair cools and undergoes a pressure drop while producing the work whichdrives the shaft 224, which in turn spins a portion of a generator 226for generating power. After expansion the air flows from the turbine 218to an air outlet 228 in step 5 j, typically for release to atmosphere.The power generation system 202 can also include a shaft 230 for thecompressors, a gear box 234 and a motor 232 for driving the compressor204.

Returning now to the Intercooler 208 and the closed loop oil system, theflow of the oil which supports the heat energy transfer described abovewill now be described. According to exemplary embodiments, oil isinitially heated in the Intercooler 208 by the exhaust air from theaxial compressor 204. Other types of compressors may be used in thepower generation system 202. This heated oil is transferred from theIntercooler 208 by, e.g., a hot oil pump 236, to the insulated hot oiltank 220. As previously described, heat is transferred from the hot oilto the compressed air when released from the cavern 216. This cooled oilis then pumped by a cold oil pump 238 to a cold oil tank 240 which istypically not insulated. From there the cooled oil is pumped back to theIntercooler 208 to continue the process again. The oil used for thisclosed loop heat transfer process can have a high specific heat. The oilmay be any di-thermic oil, for example, a Dowtherm fluid that has aspecific heat of 2.3 kJ/kg-K at substantially 250° C.

According to an exemplary embodiment, an illustrative example withvalues of pressures and temperatures of the air and oil at variouspoints of the system shown in FIG. 2 is shown in FIG. 3. These valuesare exemplary and not intended to limit the embodiments. The system inFIG. 3 will operate as described above with respect to the system shownin FIG. 2 and thus this description is omitted.

According to another exemplary embodiment, heat energy can be capturedand stored for future use in a power generation system 402 as shown inFIG. 4. The power generation system 402 includes a modified AA-CAESsystem which stores the heat energy, which is typically lost between anaxial compressor 404 and a radial compressor 408, for use during peak ornear peak load conditions. By capturing this heat energy there can beapproximately an 8-10 percent improvement in an overall operatingefficiency of the power generation system 402. This system will now bedescribed by generally following the flow of air in the system startingwith air intake to the axial compressor 404. Initially in step 7 a, airis taken into an axial compressor 404 and compressed during which theair is put under pressure and undergoes an increase in temperature. Thisair is exhausted from the axial compressor 404 in step 7 b, andundergoes heat exchange (i.e., heats an oil or another flow of air) withan insulated hot oil tank 406. The cooled air flow then, in step 7 c,departs the insulated hot oil tank 406 and enters the first radialcompressor 408. The air is then compressed by the first radialcompressor 408, exits the first radial compressor 408 and in step 7 denters a second radial compressor 410 for further compression. Thenumber of radial compressors can be different and also the type ofcompressors may be different.

The air flow then goes in step 7 e from the second radial compressor 410to an energy storage unit, e.g., a Thermal Energy Store 412. The hotcompressed air from the second radial compressor 410 is then cooled bythe Thermal Energy Store 412. The heat energy is stored in the ThermalEnergy Store 412 for future use and any water that is generated by thecooling process is drained off. The cooled compressed air is then sentto a Safety Cooler 414 in step 7 f, where the air is further cooledprior to being sent in step 7 g to a storage facility, e.g., cavern 416.This storage of the compressed air in the cavern 416 and the storage ofthe heat energy in the Thermal Energy Store 412 typically occurs duringnon-peak demand operation of the power generation system 402.

When the demand on the power generation system 402 increases to adesired point, energy output can be increased by releasing the storedcompressed air back into the system to drive an expander 418, e.g., aturbine. For example, the cavern 416 releases some of the storedcompressed air in step 7 h which undergoes preheating at the insulatedhot oil tank 406. The released compressed air then flows to the ThermalEnergy Store 412 for heating in step 7 i. Heat energy is transferredfrom the Thermal Energy Store 412 to the compressed air and the heatedcompressed air flows to a particle filter 420 in step 7 j. The heatedcompressed air then flows in step 7 k from the particle filter 420 to anexpansion section of turbine 418. During expansion the air cools andundergoes a pressure drop while producing the work which drives theshaft 422 which in turn spins a portion of a generator 424 forgenerating power. After expansion the air flows from the turbine 418 toan air outlet 426 in step 7 l, typically for release to atmosphere.Power generation system 402 can also include a shaft 428 for thecompressors, a gear box 430 and a motor 432.

According to an exemplary embodiment, an illustrative example withvalues of the pressures and temperatures of the air and oil at variouspoints of the system shown in FIG. 4 is shown in FIG. 5. These valuesare exemplary and not intended to limit the embodiments. The system inFIG. 5 will operate as described above with respect to the system shownin FIG. 4 thus this description is omitted.

According to another exemplary embodiment, an air handling unit 604 anda vapor absorption chiller 606 can be implemented in the beginningstages of a power generation system 602 as shown in FIG. 6. This allowsthe power generation system 602 to cool the air going into the axialcompressor 608, remove moisture from this air (which in turn canreduce/remove the need for removing moisture from the air downstream atthe Thermal Energy Store 12) and to reduce the temperature of theexhaust air from the axial compressor. This system will now be describedby generally following the flow of air in the system up to the firstradial compressor 610 followed by describing the fluid loops in the airhandling unit 604 and the vapor absorption chiller 606. Initially instep 9 a, air is brought into the air handling unit 604 and cooled,moisture is removed and the air is then taken into the axial compressor608. The air is then compressed in the axial compressor 608, duringwhich the air is put under pressure and undergoes an increase intemperature. This air is exhausted from the axial compressor 608 in step9 b, and undergoes heat exchange within a vapor absorption chiller 606.The cooled air flow then, in step 9 c, departs the vapor absorptionchiller 606 and enters the first radial compressor 610. The air is thencompressed by the first radial compressor 610, exits the first radialcompressor 610 and in step 9 d enters a second radial compressor 10 forfurther compression. Elements 10-30 are similar to those shown in FIG. 1thus their description is omitted.

According to exemplary embodiments, the vapor absorption chiller 606acts as a heat exchanger which in turn allows the exhaust air from theaxial compressor 608 to be cooled to the desired temperature, as well asallowing the air handling unit 604 to cool the air prior to air enteringthe axial compressor 608 as will now be described with respect to FIG.7. Initially, air enters the air handling unit 604 and is cooled by acooling loop 702. Cooling loop 702 can include chilled water or a glycolsolution. Additionally, moisture is removed from the air. This cooledair then goes to the axial compressor 608. The hot exhaust from theaxial compressor 608 enters the vapor absorption chiller 606 and iscooled enroute to the first radial compressor 610 by exchanging heatwith a refrigerant in a generation stage 704.

According to exemplary embodiments, the refrigerant vapor within thevapor absorption chiller 606 is evaporated during the generation stage704 and flows to a condenser 706. The condenser 706 includes a heatexchanger 708 and outputs a liquid refrigerant which in turn cools thecooling loop 702 as shown in heat exchanger 710. This refrigerant isthen cooled by cooling loop 712 and pumped back by pump 714 to thegeneration stage 704. Additionally, some portion of the refrigerant thatremains in a liquid form from the generation stage 704 enters the heatexchanger 710 and is also cooled by the cooling loop 712 prior to beingpumped back to the generation stage 704.

According to an exemplary embodiment, an illustrative example withvalues of the pressures and temperatures of the air and oil at variouspoints of the system shown in FIG. 6 is shown in FIG. 8. These valuesare exemplary and not intended to limit the embodiments. The system inFIG. 8 will operate as described above with respect to the system shownin FIG. 6 thus this description is omitted.

While the above described exemplary embodiments have shown threecompressors in series and capturing the heat energy between the axialand the radial compressors, other exemplary variations exist. Forexample, other quantities and types of compressors could be used, suchas one axial and one radial compressor. Additionally, heat energy can becaptured for future use from the exhaust of other compressors asdesired.

Utilizing the above-described exemplary systems according to exemplaryembodiments, a method for capturing heat energy in a power generationsystem is shown in the flowchart of FIGS. 9 and 10. The method includes:a step 902 of exhausting a first compressed, heated air flow from afirst compressor; a step 904 of storing an oil in an insulated storagetank; a step 906 of receiving the first compressed heated air flow atthe insulated storage tank; a step 908 of transferring heat energy fromthe first compressed heated air flow to the oil at the insulated storagetank; a step 910 of transferring heat energy from the oil after beingheated, to a cooled, compressed air at the insulated storage tank; astep 912 of exhausting a second compressed, heated air flow by a secondcompressor; a step 914 of storing heat energy from the secondcompressed, heated air flow at an energy storage unit; a step 916 ofstoring the cooled, compressed air received from the energy storage unitat a storage facility; and a step 918 of selectively releasing thecooled, compressed air for use in power generation by the storagefacility.

Utilizing the above-described exemplary systems according to exemplaryembodiments, a method for cooling air in a power generation system isshown in the flowchart of FIG. 11. The method includes: a step 1102 ofreceiving air at an air handling unit; a step 1104 of cooling the air atthe air handling unit to obtain a cooled air; a step 1106 of removingmoisture from the cooled air at the air handling unit to obtain acooled, dry air; a step 1108 of compressing air by a first compressor; astep 1110 of exhausting a first compressed, heated air flow from thefirst compressor; a step 1112 of transferring heat energy between aplurality of mediums including the compressed, heated air at a vaporabsorption chiller; a step 1114 of cooling the first compressed, heatedair flow at the vapor absorption chiller; a step 1116 of compressing thecooled first compressed, heated air flow at a second compressor; and astep 1118 of exhausting a second compressed, heated air flow from thesecond compressor.

The above-described exemplary embodiments are intended to beillustrative in all respects, rather than restrictive, of the presentinvention. Thus the present invention is capable of many variations indetailed implementation that can be derived from the descriptioncontained herein by a person skilled in the art. All such variations andmodifications are considered to be within the scope and spirit of thepresent invention as defined by the following claims. No element, act,or instruction used in the description of the present application shouldbe construed as critical or essential to the invention unless explicitlydescribed as such. Also, as used herein, the article “a” is intended toinclude one or more items.

This written description uses examples of the subject matter disclosedto enable any person skilled in the art to practice the same, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the subject matter is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims.

1. A system for cooling air in a power generation system, the systemcomprising: an air handling unit configured to receive air, to cool theair, and to remove moisture from the air; a first compressor fluidlyconnected to the air handling unit and configured to receive the airfrom the air handling unit and to exhaust a first compressed, heated airflow; a vapor absorption chiller connected to the first compressorconfigured to transfer heat energy between a plurality of mediums and tocool the first compressed, heated air flow; a second compressorconnected to the vapor absorption chiller configured to receive thecooled first compressed, heated air flow and to exhaust a secondcompressed, heated air flow; an energy storage unit connected to thesecond compressor and configured to store heat energy from the secondcompressed, heated air flow; and a storage facility connected to theenergy storage unit and configured to store a cooled, compressed airreceived from the energy storage unit and to selectively release thecooled, compressed air back into the power generation system.
 2. Thesystem of claim 1, wherein the vapor absorption chiller configured totransfer heat energy between a plurality of mediums and to cool thefirst compressed, heated air flow comprises: a first heat exchangerconfigured to transfer heat energy from the first compressed, heated airflow to a refrigerant; a second heat exchanger fluidly connected to thefirst heat exchanger and configured to cool and to condense therefrigerant; a third heat exchanger fluidly connected to the second heatexchanger and configured to transfer heat energy from a first fluid tothe refrigerant, wherein the first fluid then cools the air received bythe air handling unit; and a fourth heat exchanger fluidly connected tothe third heat exchanger and configured to transfer heat energy from therefrigerant to a second fluid.
 3. The system of claim 2, wherein thefirst fluid is one of water or glycol.
 4. The system of claim 2, whereinthe vapor absorption chiller further comprises: a pump configured topump the refrigerant.
 5. The system of claim 1, wherein the firstcompressor is an axial compressor and the second compressor is a radialcompressor.
 6. The system of claim 2, wherein the third heat exchangeris connected to both the air handling unit and the vapor absorptionchiller.
 7. The system of claim 1, wherein the cooled first compressed,heated air flow is at a temperature of substantially 180° C.
 8. A systemfor cooling air in a power generation system, the system comprising: anair handling unit configured to receive air, to cool the air and toremove moisture from the air; a first compressor fluidly connected tothe air handling unit and configured to receive the air from the airhandling unit and to exhaust a first compressed, heated air flow; avapor absorption chiller connected to the first compressor andconfigured to transfer heat energy between a plurality of mediums and tocool the first compressed, heated air flow; and a second compressorconnected to the vapor absorption chiller and configured to receive thecooled first compressed, heated air flow and to exhaust a secondcompressed, heated air flow.
 9. The system of claim 8, wherein the vaporabsorption chiller configured to transfer heat energy between aplurality of mediums and to cool the first compressed, heated air flowcomprises: a first heat exchanger configured to transfer heat energyfrom the first compressed, heated air flow to a refrigerant; a secondheat exchanger fluidly connected to the first heat exchanger andconfigured to cool and to condense the refrigerant; a third heatexchanger fluidly connected to the second heat exchanger and configuredto transfer heat energy from a first fluid to the refrigerant, whereinthe fluid then cools the air received by the air handling unit; and afourth heat exchanger fluidly connected to the third heat exchanger andconfigured to transfer heat energy from the refrigerant to a secondfluid.
 10. The system of claim 9, wherein the first fluid is one ofwater or glycol.
 11. The system of claim 9, wherein the vapor absorptionchiller further comprises: a pump configured to pump the refrigerant.12. The system of claim 8, wherein the first compressor is an axialcompressor and the second compressor is a radial compressor.
 13. Thesystem of claim 8, wherein the third heat exchanger is connected to boththe air handling unit and the vapor absorption chiller.
 14. The systemof claim 8, wherein the cooled first compressed, heated air flow is at atemperature of substantially 180° C.
 15. A method for cooling air in apower generation system, the method comprising: receiving air at an airhandling unit; cooling the air at the air handling unit to obtain acooled air; removing moisture from the cooled air at the air handlingunit to obtain a cooled, dry air; compressing the cooled, dry air by afirst compressor; exhausting a first compressed, heated air flow fromthe first compressor; transferring heat energy between a plurality ofmediums including the compressed, heated air at an vapor absorptionchiller; cooling the first compressed, heated air flow at the vaporabsorption chiller; compressing the cooled first compressed, heated airflow at a second compressor; and exhausting a second compressed, heatedair flow from the second compressor.
 16. The method of claim 15, furthercomprising: transferring heat energy from the first compressed, heatedair flow to a refrigerant at a first heat exchanger in the vaporabsorption chiller; cooling the refrigerant at a second heat exchangerin the vapor absorption chiller; condensing the refrigerant at thesecond heat exchanger in the vapor absorption chiller; transferring heatenergy from a first fluid to the refrigerant at a third heat exchangerin the vapor absorption chiller, wherein the fluid then cools the airreceived by the air handling unit; and transferring heat energy from therefrigerant to a second fluid at a fourth heat exchanger in the vaporabsorption chiller.
 17. The method of claim 16, wherein the first fluidis one of water or glycol.
 18. The method of claim 16, furthercomprising: pumping the refrigerant by a pump.
 19. The method of claim15, wherein the first compressor is an axial compressor.
 20. The methodof claim 15, wherein the cooled first compressed, heated air flow is ata temperature of substantially 180° C.